1. Field of the invention
The present invention relates to a method for forming a metallic barrier layer to connect electrically multi-layers in the manufacturing process of semiconductor devices, and in particular, relates to a method for forming a diffusion metallic barrier layer of a TiNO structure.
2. Description of the Prior Art
In general, aluminum alloy is used with a metallic barrier layer so as to prevent the junction spiking and decrease the resistance in a contact portion when a sub-micron device having a shallow junction is manufactured.
On the other hand, a double structure comprising Ti/TiN films is mainly used as the metallic barrier layer in convenience. The TiN film is used as a diffusion barrier to intercept the diffusing of Si atoms between the metal layers. For perfect intercepting, a composition rates of TiN must be 1 to 1.
However, the present sputtering equipment has difficulty in controlling the rates to be 1 to 1.
Also, the TiN film is not efficient in intercepting the diffusing of the atoms because of its porousness.